All weiler wheels are resin bond formulated for fast, high quality grinding and cutting, and are reinforced with fiberglass webbing to provide stability. Weiler"s type 27 wheels contain no fillers and are made with 100 percentage abrasive grain to maximize cut rate. Long life - offers longer life than the softer wheel grade (N), Ideal for all general. Purpose grinding on structural steel, or in foundries or heavy fabrication applications.